Reference is made to my copending application Ser. No. 663,643, filed Oct. 22, 1984.
Prior to the present invention, various methods were available for making the triphenylsulfonium chloride having the formula ##STR2## which thereafter could be metathesized with an alkali, or alkaline earth metal of a polyhalo metal or a metalloid salt. Some of these alkali or alkaline earth metal halo salts are preferably included within the formula EQU MYX.sub.n ( 2)
where M is hydrogen or an alkali metal, for example, sodium, potassium or lithium, or an alkaline earth metal such as magnesium, barium, zinc, etc., Y is a metal or metalloid, for example, boron, phosphorous, antimony or arsenic, X is a halogen radical such as fluorine and n has a value of 4-6, inclusive.
One method is shown by Pitt, U.S. Pat. No. 2,807,648, using a direct Friedel Crafts condensation of an aromatic hydrocarbon employing aluminum chloride. Another procedure is shown by Crivello U.S. Pat. No. 4,374,066 assigned to the same assignee as the present invention employing diphenyl sulfide and aluminum chloride in combination with chlorine. Another procedure is shown by Smith U.S. Pat. No. 4,173,476 employing a mixture of diaryl sulfide and diarylsulfoxide in the presence of a strong acid. Although the aforementioned methods were useful for making the triarylsulfonium salts of formula (1), it was often found that the yields provided by the reaction were unsatisfactory or that the reactants such as diphenylsulfoxide rendered the method uneconomic. In addition, several of the aforementioned procedures required the isolation or separation of intermediates formed during the reaction before the desired end product was obtained. For example, the metathesis of the triarylsulfonium halide with an alkali metal or alkaline earth metal polyhalo metal or metalloid salt of formula (2), often requires the prior isolation of the triarylsulfonium halide.
The present invention is based on the discovery that polyarylsulfide, for example, compounds selected from EQU RR.sup.1 S, and (3) ##STR3## where R is selected from C.sub.(6-14) aryl radicals and substituted C.sub.(6-14) aryl radicals, R.sup.1 is selected from R radicals and EQU RQR.sup.3 (--SR.sup.4 --).sub.b,
R.sup.2, R.sup.3 and R.sup.4 are selected from divalent C.sub.(6-14) arylene radicals, and substituted C.sub.(6-14) divalent arylene radicals, Q is selected from --O--, --S(O)--, --S-- and mixtures thereof, Z is a member selected from --O--, --S-- and --C(R.sup.5).sub.2 --, R.sup.5 is selected from hydrogen and C.sub.(1-8) monovalent organo radicals and a is a whole number equal to 0 or 1 and b is a whole number equal to 0 to 3 inclusive, can be partially oxidized to produce a fleeting mixture of diarylsulfide and diarylsulfoxide in situ, which thereafter, while in the presence of a dehydrating agent and a strong protonic acid, can be converted in situ, to the corresponding triarylsulfonium acid salt.
The triarylsulfonium acid salt can be directly metathesized without isolation with a polyhalo metal or metalloid salt of formula (2) to produce a triarylsulfonium polyhalo metal or metalloid salt in high yields.